Am Donnerstag, 15. Dezember 2005 14:27 schrieb cbbrowne at ca.afilias.info:
> The "search for plpgsql.so" is there to ensure that it'll be there at
> runtime in that plenty of the Slony-I functionality operates as pl/pgsql
> functions.

But looking for the file doesn't tell you anything about that.  It doesn't say 
that the file can be loaded or that you are even looking at the right server 
instance (or even that the file indeed does contain PL/pgSQL).  Slony in 
particular will likely run on two or more hosts, and you don't know anything 
about the other hosts.

When you finally load the slony support functions, the PostgreSQL server is 
perfectly capable of telling the user "plpgsql does not exist, run 
createlang".  What's wrong with that?  Users can install plpgsql then, and 
there is no need to recompile anything.

Note that the slony build process doesn't even require a PostgreSQL server to 
be installed.  Shouldn't you warn about that?